This invention is directed to an improved electronic wristwatch digital display and in particular to the use of a digital display including an oxidation-reduction compound and elctronic wristwatch circuitry for effecting selective activation thereof.
Very precise wristwatches of the mechanical variety have been available for a long time. Such mechanical wristwatches utilize a mechanism in which a balance mainspring is utilized as the time standard. Display hands are rotated by a gear train which gear train is driven in response to the oscillatory period determined by the balanced mainspring.
The gradual incorporation of electronic circuitry into wristwatches to replace mechanical mechanisms has resulted in the development of all electronic timepieces. The substitution of a battery for a mainspring as a power source, and a tuning fork as a time standard for a balance with the mainspring were two early developments. Thereafter, the use of quartz crystal vibrators as the time standard in an oscillator circuit provided highly accurate electronic wristwatches.
Nevertheless, although such developments have occasioned a complete substitution of electronic elements for mechanical elements in the timekeeping movement of an electronic timepiece, most electronic wristwatches still include conventional analog hands mounted to rotate around a dial disk for effective display of time. Although the use of digital display elements such as light emitting diodes and liquid crystals have been utilized, such digital display elements have been less than completely satisfactory. Specifically, liquid crystals do not provide a clear contrast and are not as reliable as the remaining electronic components in the timepiece. On the other hand, light emitting diodes cause excess current consumption and hence dissipate the battery in too short a time. Accordingly, an electronic wristwatch display wherein the numbers displayed thereby are clear, highly reliable and utilize a minimum of current are desired.